Compression Deformation Behavior of As-cast AZ91 Magnesium Alloy

Compression tests of as-cast AZ91 magnesium alloy were performed on Gleeble-1500 at deformation temperature ranging from 473 to 673K and strain rate from 0.005 to 5 s-1.The results show that the flow stress of the tested alloy decreases with the increase of deformation temperature and increases with the increase of strain rate,which can be represented by a Zener-Hollomon parameter in the power-type equation.Parameters β,A and the deformation activation energy Q in the flow stress equation are 0.1015,2.386 3×109 and 175.667 kJ/mol respectively,derived from experiment data through multiple regression analysis.AZ91 magnesium alloy shows different characteristics of the microstructure at different deformation temperature.The microstructure of AZ91 magnesium alloy mainly consists of twinning and slip band at 473K and dynamic recrystallization grain between 573 and 673 K,respectively.Research results may lay the foundation for systematic study on plastic processing of AZ91 magnesium alloy.